INNATE AND ADAPTIVE MECHANISMS IN ARTHRITIS

描述（由申请人提供）：风湿性关节炎导致严重残疾和死亡率增加。目前对其发病机制的研究主要集中在宿主免疫功能失调而产生病理变化的机制上。巨噬细胞移动抑制因子（MIF）是由先天性（单核细胞/巨噬细胞）和适应性（T细胞）免疫细胞产生的免疫应答的上游调节因子。我们发现人类MIF基因（Mif）由功能不同的等位基因编码，并且高表达的Mif等位基因在类风湿性关节炎患者中过度表达。我们还鉴定了细胞表面蛋白CD 74是MIF的细胞受体。我们认为，先天性或适应性免疫反应和其结合到CD 74的MIF过量生产发挥内在的作用，类风湿关节炎的发病机制。本申请的目的是确定炎症性关节炎中MIF产生和作用的细胞基础。中心假设是炎性关节炎是由于单核细胞/巨噬细胞或T细胞过度产生MIF，加上通过与CD 74结合而激活靶细胞的MIF。这项拟议研究的基本原理是，一旦了解了炎症性关节炎中MIF产生和作用的分子基础，那么就可以更准确地了解这种疾病中的免疫失调。我们将通过追求三个具体目标来测试我们的假设并实现本申请的目的：1）通过研究单核细胞特异性和T细胞特异性Mif-Knockout小鼠来确定MIF在炎性关节炎中的作用。我们将研究Mif-floxed小鼠关节炎的发展，使单核细胞衍生的MIF或T细胞衍生的MIF基因缺陷。2)建立体内MIF/CD 74相互作用的病理作用。我们将通过给患有实验性关节炎的野生型小鼠施用中和性抗CD 74 mAb或可溶性CD 74蛋白（sCD 74）来确定MIF/CD 74相互作用的病理重要性。3)明确高表达与低表达的Mif等位基因在人单核细胞和T细胞的MIF产生、细胞活化和下游细胞因子表达中的作用。我们将从类风湿性关节炎患者中获得单核细胞和T细胞，分析Mif基因型，并研究MIF的产生、细胞活化和下游细胞因子的表达。这些结果将是重要的，因为它们将提供一个更精确的理解MIF的作用，连接先天性和适应性免疫的途径，并成为失调，产生炎症性关节炎。此外，他们将提供一个科学的理由来确定个人谁可能是一个高风险的严重类风湿性关节炎-基于他们的Mif等位基因，以便采取措施，以更好地治疗他们的糜烂性疾病。

DESCRIPTION (provided by applicant): Rheumatoid arthritis causes significant disability and increased mortality. Research into its pathogenesis currently focuses on the mechanisms by which host immunity becomes dysregulated to produce pathologic changes. Macrophage migration inhibitory factor (MIF) is an upstream regulator of the immune response that is produced both by innate (monocyte/macrophage) and adaptive (T cell) immune cells. We have discovered that the human MIF gene (Mif) is encoded by functionally distinct alleles, and that high-expression Mif alleles are over-represented in patients with rheumatoid arthritis. We also have identified the cell surface protein, CD74, to be a cellular receptor for MIF. We suggest that MIF overproduction by the innate or the adaptive immune response and its binding to CD74 play an intrinsic role in the pathogenesis of rheumatoid arthritis. The objective of this application is to define the cellular basis of MIF production and action in inflammatory arthritis. The central hypothesis is that inflammatory arthritis results from an overproduction of MIF by monocytes/macrophages or by T cells, coupled with MIF activation of target cells by binding to CD74. The rationale for this proposed research is that once the molecular basis for MIF production and action in inflammatory arthritis is known, then a more precise understanding of immune dysregulation in this disease will have been achieved. We will test our hypothesis and accomplish the objective of this application by pursuing three specific aims: 1) Define MIF's Role in Inflammatory Arthritis by Studying Monocyte-specific and T cell-specific Mif-Knockout Mice. We will examine arthritis development in Mif-floxed mice made genetically-deficient either for monocyte-derived MIF, or for T cell-derived MIF. 2) Establish the Pathologic Role of the MIF/CD74 Interaction In Vivo. We will establish the pathologic importance of the MIF/CD74 interaction by administering a neutralizing anti- CD74 mAb, or a soluble CD74 protein (sCD74), to wild-type mice with experimental arthritis. 3) Define the Role of High- versus Low-expression Mif alleles in MIF Production, Cellular Activation, and Downstream Cytokine Expression by Human Monocytes and T Cells. We will obtain monocytes and T cells from patients with rheumatoid arthritis, analyze the Mif genotype, and study MIF production, cellular activation, and downstream cytokine expression. These results will be significant because they will provide a more precise understanding of MIF's role in the pathways that link innate and adaptive immunity, and which become dysregulated to produce inflammatory arthritis. Moreover, they will provide a scientific rationale for identifying individuals who may be a high risk for severe rheumatoid arthritis - based on their Mif alleles, so that steps can be taken to better treat their erosive disease.